From c2cdf60ffcc8ec8230d17aa9a8e699b9387db7a8 Mon Sep 17 00:00:00 2001
From: Alexey Khit <alexey.khit@gmail.com>
Date: Wed, 1 Mar 2023 18:03:11 +0300
Subject: [PATCH] Code refactoring

Code refactoring
---
 cmd/webrtc/README.md     |  6 ++++++
 cmd/webrtc/candidates.go |  2 +-
 pkg/tcp/request.go       |  3 +--
 pkg/webrtc/README.md     | 11 +++++++++++
 pkg/webrtc/server.go     |  2 +-
 www/webrtc-sync.html     | 25 +++++++++++++------------
 www/webrtc.html          |  2 +-
 7 files changed, 34 insertions(+), 17 deletions(-)
 create mode 100644 cmd/webrtc/README.md
 create mode 100644 pkg/webrtc/README.md

diff --git a/cmd/webrtc/README.md b/cmd/webrtc/README.md
new file mode 100644
index 00000000..8baf575c
--- /dev/null
+++ b/cmd/webrtc/README.md
@@ -0,0 +1,6 @@
+## Userful links
+
+- https://www.ietf.org/archive/id/draft-ietf-wish-whip-01.html
+- https://www.ietf.org/id/draft-murillo-whep-01.html
+- https://github.com/Glimesh/broadcast-box/
+- https://github.com/obsproject/obs-studio/pull/7926
diff --git a/cmd/webrtc/candidates.go b/cmd/webrtc/candidates.go
index 1ce249ea..af99ca0c 100644
--- a/cmd/webrtc/candidates.go
+++ b/cmd/webrtc/candidates.go
@@ -61,7 +61,7 @@ func asyncCandidates(tr *api.Transport, cons *webrtc.Conn) {
 		if candidates, ok := ctx["candidate"].([]string); ok {
 			// process candidates that receive before this moment
 			for _, candidate := range candidates {
-				cons.AddCandidate(candidate)
+				_ = cons.AddCandidate(candidate)
 			}
 
 			// remove already processed candidates
diff --git a/pkg/tcp/request.go b/pkg/tcp/request.go
index 94e0bd25..f0b76edb 100644
--- a/pkg/tcp/request.go
+++ b/pkg/tcp/request.go
@@ -84,8 +84,7 @@ func Do(req *http.Request) (*http.Response, error) {
 
 		req.Header.Set("Authorization", header)
 
-		res, err = client.Do(req)
-		if err != nil {
+		if res, err = client.Do(req); err != nil {
 			return nil, err
 		}
 	}
diff --git a/pkg/webrtc/README.md b/pkg/webrtc/README.md
new file mode 100644
index 00000000..24282e08
--- /dev/null
+++ b/pkg/webrtc/README.md
@@ -0,0 +1,11 @@
+## StateChange
+
+1. offer = pc.CreateOffer()
+2. pc.SetLocalDescription(offer)
+3. OnICEGatheringStateChange: gathering
+4. OnSignalingStateChange: have-local-offer
+*. OnICEGatheringStateChange: complete
+5. pc.SetRemoteDescription(answer)
+6. OnSignalingStateChange: stable
+7. OnICEConnectionStateChange: checking
+8. OnICEConnectionStateChange: connected
diff --git a/pkg/webrtc/server.go b/pkg/webrtc/server.go
index e1586e44..7021f078 100644
--- a/pkg/webrtc/server.go
+++ b/pkg/webrtc/server.go
@@ -57,7 +57,7 @@ func (c *Conn) GetAnswer() (answer string, err error) {
 		return
 	}
 
-	return desc.SDP, nil
+	return c.pc.LocalDescription().SDP, nil
 }
 
 func (c *Conn) GetCompleteAnswer() (answer string, err error) {
diff --git a/www/webrtc-sync.html b/www/webrtc-sync.html
index f7bc3eb8..36cf1189 100644
--- a/www/webrtc-sync.html
+++ b/www/webrtc-sync.html
@@ -27,14 +27,17 @@
 <video id="video" autoplay controls playsinline muted></video>
 <script>
     // support api_path
-    let baseUrl = location.origin + location.pathname.substr(
+    const baseUrl = location.origin + location.pathname.substr(
         0, location.pathname.lastIndexOf("/")
     );
 
-    let pc = new RTCPeerConnection({
-        iceServers: [{urls: 'stun:stun.l.google.com:19302'}]
+    const pc = new RTCPeerConnection({
+        iceServers: [
+            {urls: 'stun:stun.l.google.com:19302'},
+        ]
     });
-    pc.onicegatheringstatechange = async () => {
+
+    pc.addEventListener('icegatheringstatechange', async () => {
         if (pc.iceGatheringState !== 'complete') return;
 
         let r = await fetch(`${baseUrl}/api/webrtc${location.search}`, {
@@ -43,20 +46,18 @@
         await pc.setRemoteDescription({
             type: 'answer', sdp: await r.text()
         });
-    }
-    pc.ontrack = ev => {
+    });
+    pc.addEventListener('track', ev => {
         let video = document.getElementById('video');
         if (video.srcObject === null) {
             video.srcObject = ev.streams[0];
         }
-    }
+    });
 
-    pc.addTransceiver('video');
-    pc.addTransceiver('audio');
+    pc.addTransceiver('video', {direction: 'recvonly'});
+    pc.addTransceiver('audio', {direction: 'recvonly'});
 
-    pc.createOffer({
-        offerToReceiveVideo: true, offerToReceiveAudio: true
-    }).then(offer => {
+    pc.createOffer().then(offer => {
         pc.setLocalDescription(offer);
     });
 </script>
diff --git a/www/webrtc.html b/www/webrtc.html
index 39954bdc..1463b7b7 100644
--- a/www/webrtc.html
+++ b/www/webrtc.html
@@ -61,7 +61,7 @@
 
             if (ev.candidate !== null) {
                 ws.send(JSON.stringify({
-                    type: 'webrtc/candidate', value: ev.candidate.toJSON().candidate
+                    type: 'webrtc/candidate', value: ev.candidate.candidate
                 }));
             }
         }